Article Contents
Article Contents

# On a transmission eigenvalue problem for a spherically stratified coated dielectric

• Suppose that the boundary of the unit ball in $R^3$ is coated with a very thin layer of a highly conductive material and the refractive index $n(x)$ inside the ball is spherically stratified. We show that in this case the set of transmission eigenvalues behave quite differently than in the previous studied case of an uncoated ball. In particular, if the index of refraction varies smoothly across the boundary of the unit ball we show that complex eigenvalues always exist and accumulate on the real axis and that the real and complex eigenvalues uniquely determine the index of refraction without any restriction on its magnitude.
Mathematics Subject Classification: Primary: 30D15, 34B09, 34B24, 35Q60.

 Citation:

•  [1] T. Aktosun, D. Gintides and V. G. Papanicolaou, The uniqueness in the inverse problem for transmission eigenvalues for the spherically symmetric variable-speed wave equation, Inverse Problems, 27 (2011), 115004, 17pp.doi: 10.1088/0266-5611/27/11/115004. [2] T. Aktosun and V. G. Papanicolaou, Reconstruction of the wave speed from transmission eigenvalues for spherically symmetric variable-speed wave equation, Inverse Problems, 29 (2013), 055007, 19pp.doi: 10.1088/0266-5611/29/6/065007. [3] A. Baker, Transcendental Number Theory, Cambridge University Press, Cambridge, 1975. [4] F. Cakoni and D. Colton, A Qualitative Approach to Inverse Scattering Theory, Applied Mathematical Sciences Series Volume 188, Sringer, New York 2014.doi: 10.1007/978-1-4614-8827-9. [5] F. Cakoni, D. Colton and D. Gintides, The interior transmission eigenvalue problem, SIAM J. Math Anal., 42 (2010), 2912-2921.doi: 10.1137/100793542. [6] R. Courant and D. Hilbert, Methods of Mathematical Physics, Volume I, Interscience Publishing, New York, 1953. [7] D. Colton and R. Kress, Inverse Acoustic and Electromagnetic Scattering Theory, 3rd ed., Applied Mathematical Sciences, 93. Springer, New York, 2013.doi: 10.1007/978-1-4614-4942-3. [8] D. Colton and Y. J. Leung, Complex Eigenvalues and the inverse spectral problem for transmission eigenvalues, Inverse Problems, 29 (2013), 104008, 6pp.doi: 10.1088/0266-5611/29/10/104008. [9] D. Colton, Y. J. Leung and S. Meng, Distribution of complex transmission eigenvalues for spherically stratified media, Inverse Problems, 31 (2015), 035006, 19pp.doi: 10.1088/0266-5611/31/3/035006. [10] R. Duffin and A. C. Schaeffer, Some properties of functions of exponential type, Bull. Amer. Math. Soc., 44 (1938), 236-240.doi: 10.1090/S0002-9904-1938-06725-0. [11] B. Levin, Distribution of Zeros of Entire Functions, American Mathematical Society Translation, Providence, Rhode Island, R.I., 1980. [12] J. McLaughlin and P. Polyakov, On the uniqueness of a spherically symmetric speed of sound from transmission eigenvalues, J. Differential Equations, 107 (1994), 351-382.doi: 10.1006/jdeq.1994.1017. [13] H. Pham and P. Stefanov, Weyl asymptotics for the transmission eigenvalues for a constant index of refraction, Inverse Prob. Imaging, 8 (2014), 795-810.doi: 10.3934/ipi.2014.8.795. [14] W. Rundell and P. Sacks, Reconstruction techniques for classical inverse Sturm-Liouville problems, Math. Comp., 58 (1992), 161-183.doi: 10.1090/S0025-5718-1992-1106979-0. [15] J. Sylvester, Transmission eigenvalues in one dimension, Inverse Problems, 29 (2013), 104009, 11pp.doi: 10.1088/0266-5611/29/10/104009. [16] G. Wei and H. Xu, Inverse spectral analysis for the transmission eigenvalue problem, Inverse Problems, 29 (2013), 115012, 24pp.doi: 10.1088/0266-5611/29/11/115012. [17] W. Young, Introduction to Nonharmonic Fourier Series, Academic Press, San Diego, 2001.